Clean campaign links for analytics.
Where the traffic comes from (newsletter, exitfounder, x)
referral, email, cpc, social
launch, spring_sale
Paid keyword (optional)
Variant / placement (optional)
https://acme.example/pricing?utm_source=exitfounder&utm_medium=referral&utm_campaign=launch
Values are lower-cased with spaces → underscores so analytics groups them consistently.